PURPOSE: To obtain the impeller integrated with the body and vane parts with high accuracy in less working steps by subjecting the impeller body to bulging and fixed push-press working.
CONSTITUTION: The impeller body 2 of metal plate such as iron or steel plate or stainless steel plate is subjected to bulging at the specified positions to form the bulged parts 1 of arc-form in section. Next, the bulged parts 1 is subjected to fixed push-press working by using fixed push-press working dies to form the blade parts 1' or 1" in such a manner that the outer side walls of the bulged parts 1 become the perpendicular sides of the right-angled triangle bulging at a right angle. Thence, the outside blanking part 3 and central blanking part 4 of the impeller body 2 are blanked, after which burring is done and thread cutting is applied to the inside circumferential surface to form a boss part or a seamless pipe is welded to provide the boss part.
KAWASE HISAO
TAKEZOE AKINOBU
